The present invention relates to a method for laminating woody fiberboard for various kinds of usage.
A woody fiberboard, a so called MDF board (Medium Density Fiberboard) is produced by molding into a plate form under the heat and pressure, fibers obtained by splitting wood chips into a cotton substance along with an adhesive. The MDF board is used for various materials for construction, furniture, washstands and kitchen units owing to its light weight, high strength and water resistance.
The MDF has remarkably excellent characteristics in that sapling and thinned wood can be utilized as a raw material and therefore, it is a new material attracting world wide attention in a view of the effective utilization of forest resources and the global environmental issues, such as the world wide shortage of forest resources.
Furthermore, the MDF board has the following excellent characteristics; a warp, twisting and cracking which are liable to occur in natural wood, can be prevented. It has feeling that is equivalent to natural wood. It has strength and toughness that are higher by 1.5 to 3 times than natural wood. It is stable against water and moisture. No unevenness is formed on the surface during a long term use.
However, due to the production process thereof comprising pressing under the heat and pressure, there is a difference in material and specific gravity between the surface part and the central part of the article and has a problem, in that the smooth coating surface suffers immediately after coating a slight unevenness, from 3 to 6 months, because of the unevenness in degree of penetration of the coated material.
The MDF board also has a problem, in that swelling, warping and cracking at cutted ends occurs upon absorbing water.
Furthermore, the MDF board cannot be used where a certain strength is required and the thickness thereof is limited to about 40 mm at most, so that it can not be used for an article having a large thickness.
It is also impossible to produce articles having various sizes and shapes, such as an article having a curved surface and an article having a small thickness and a high strength.
The invention has been developed in order to solve the problems described above. An object of the invention is therefore to provide a method for laminating a woody fiberboard, in that woody fiberboards are laminated with increasing the strength thereof, the laminated woody fiberboard is processed by cutting into a prescribed shape and the strength of the processed article is further increased to finish the product so as to obtain an article having various sizes and shapes.
A laminated body of a woody fiberboard having various sizes and shapes can be obtained by a method for laminating a woody fiberboard comprising the steps of:
molding wood chips using an adhesive as a binder, to produce a woody fiberboard having a prescribed thickness;
impregnating or coating a single board of the woody fiberboard with a polyurethane series primer, followed by drying;
laminating by adhering two or more of the dried woody fiberboards with an aqueous polymeric isocyanate series adhesive;
processing the laminated woody fiberboard by a cutting blade into a prescribed shape;
impregnating or coating the processed article with a polyurethane series primer, followed by drying; and
impregnating or coating the dried article with one or more of a urethane series resin, a melamine series resin, a polyester series resin and a lacquer.